High training load and recovery plays an important role in training, particularly in athletic training. There has to be a balance between hard and easy training and rest both within a single training week and within longer training periods. Finding a balance between training load and recovery is a key factor in improving fitness.
Periodization is important in training. Usually athletes have several very hard training periods each year, during which both the intensity and volume of training are very high. These kinds of overreaching periods are very exhaustive but necessary for athletes to further improve their performance. However, performance can improve only if hard training is followed by adequate recovery.
Supercompensation is very incremental improvement of performance level. The results are usually shown over time and multiple training sessions. Every training session is not intended to bring supercompensation. A large part of aerobic endurance training is low intensity long duration training that prepares the capabilities of the body for harder training.
The timing of supercompensation and the recovery needs is individual and it will greatly be affected of the acute situations, such as training, stress, eating and sleeping. The real recovery is unknown until the recovery has taken place. The best and the only indisputable measure of recovery time is the change of performance. FIG. 1 shows an example of different kinds of recovery time from the same workout: quick-recovery, normal recovery and slowly recovery. Because the recovery from workout can be very different in different person and even with same person in different situations and depending on time of day, it is very important to determine the body's readiness to exercise during each exercise session.
The prior art has documented some work on the measurement of exercise workload and recovery. Nissila et al. (US 2011021319A1) have presented an apparatus for metabolic training load, mechanical stimulus, and recovery time calculation. This method's recovery time assessment is based on the measured training load/workload from the whole exercise. The method does not assess user's performance level and therefore does not provide information on the capacity of the user to perform the exercise. Furthermore, as the method is based on analysis of the workload of the whole exercise, the method can provide information only after the exercise, and the method fails to make assessment of recovery time or body's readiness to exercise during exercise. Thus, as the method does not make an assessment of the readiness of the user to do the exercise during the exercise, the method is not capable of calibrating and providing feedback already during the exercise. Saalasti et al. (U.S. Pat. No. 7,192,401 B2) have presented a method for monitoring accumulated body fatigue for determining recovery during exercise or activity. This method provides recovery information already during exercise, but does not determine person's performance level and thereby does not calibrate the recovery time. The method is not also able to provide feedback to person's readiness to exercise.
Prior art has documented work on deriving information on the accumulation of body fatigue and exhaustion due to physical workload. Bernard et al. (U.S. Pat. No. 4,883,063) have presented a method for monitoring heat stress, as especially occurring in a hot factory environment. The solution includes an assessment of recovery on the basis of heart rate measurement, during which the person has to stay at rest for few minutes. The estimation of the recovery is somewhat problematic in the described method, since it requires few minutes of rest and is not therefore applicable to continuous monitoring of recovery within dynamic changes in exercise phases and intensities. In general, the method does not involve a differential estimation of the recovery component which impairs the estimation of the recovery during dynamic exercise.